In the past, those learning to play the guitar have had to put in many hours of practice over many days before their chord hand finger muscles and calluses developed sufficient strength and toughness, respectively, such that playing would not be uncomfortable and real learning could progress. Most students with sufficient dedication continue to practice regularly until they reach a plateau in their ability wherein further improvement would demand much more of their time and resources. As far as they then care, they "know how to play". At this point, most people begin to spend much less time playing and, without the stimulation thus provided, the body begins to rid itself of those hard-won calluses. When these are gone, playing becomes somewhat of a painful experience.